A new global repressor (bvlR) of pathogenicity and tight microcolony formation in P. aeruginosa

ABSTRACT: LysR-type transcriptional regulators (LTTRs) are the most common family of transcriptional regulators found in the opportunistic pathogen Pseudomonas aeruginosa. They are known to regulate a wide variety of virulence determinants and have emerged recently as positive global regulators of pathogenicity in a broad spectrum of serious bacterial pathogens. However, in spite of their key role in modulating expression of key virulence determinants underpinning pathogenic traits associated with the process of infection, surprisingly few were found to be transcriptionally altered in co-culture with host cells. bvlR (PA14_26880) an LTTR of previously unknown function, has been shown to be induced in response to host cells, and was therefore investigated for its potential role in virulence. BvlR expression was found to play a pivotal role in regulation of acute virulence determinants such as type III secretion and exotoxin A production. In contrast, loss of bvlR led to an inability to form tight microcolonies, a key step in biofilm formation in the mucoid lung, although surface attachment was increased. bvlR was also seen to a key role in P.aeruginosa pathogenicity within the acute model of infection, Caenorhabditis elegans. Unusually for LTTRs, BvlR was shown to exert its influence exclusively through the transcriptional repression of 307 genes, including the divergently transcribed gene bvlA. This highlights the importance of BvlR as a previously uncharacterized global virulence regulator in P. aeruginosa with a key role in the transcriptional response underlying the host pathogen interaction. Six samples were analysed in total, three biological replicates of the bvlR mutant and bvlR complemented strains.

ORGANISM(S): Pseudomonas aeruginosa PAO1

SUBMITTER: Fergal O'Gara 

PROVIDER: E-GEOD-51491 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress